Cytokines Alter the Expression and Activity of the Multidrug Resistance Transporters in Human Hepatoma Cell Lines; Analysis Using RT‐PCR and cDNA Microarrays

Abstract

Pro‐inflammatory cytokines suppress the hepatic expression of the multidrug resistance transporters in rodents, indicating potential usefulness in chemotherapy. Our objective was to investigate their impact in human hepatoma cells. HuH 7 and HepG2 cells were treated with IL‐1β, IL‐6, or TNF‐α for 0–72h. Expression and activity of MDR1 and the MRP (MRP1, 2, 3, and 6) transporters were examined by RT‐PCR, efflux assays, and microarrays. Significant reductions in the MDR1‐mediated efflux of Rhodamine 123 and MDR1 mRNA levels were observed in HuH 7 cells treated with IL‐6, TNF‐α, or IL‐1β and in TNF‐α–treated HepG2 cells. However, cytokine‐treated HuH7 cells also demonstrated 1.6‐ to 2.6‐fold greater efflux of the MRP substrate, 5‐carboxyfluorescein (5‐CF) and higher MRP3 mRNA levels (p < 0.05). IL‐1β and IL‐6 treatments increased MRP activity and MRP1 mRNA levels in HepG2 cells (p < 0.05). Microarrays studies performed in IL‐6 and TNF‐α–treated HepG2 cells detected similar changes in the expression of the MDR1 and MRP transporters, but this did not reach significance. However, the microarrays confirmed cytokine‐mediated induction of several acute phase proteins. Our data suggests that although cytokine‐mediated suppression of PGP may alter drug resistance in malignant cells, these cytokines may also impose an induction in other multidrug resistance genes. © 2003 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2152–2163, 2003